JP3912082B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a multilayer ceramic electronic component such as a multilayer capacitor, and more specifically, a process of obtaining a mother multilayer body and obtaining individual multilayer ceramic electronic component unit multilayer bodies from the mother multilayer body. The present invention relates to a method for manufacturing an improved multilayer ceramic electronic component.
[0002]
[Prior art]
Conventionally, when manufacturing a multilayer ceramic electronic component such as a multilayer capacitor, a mother multilayer body in which a plurality of internal electrode patterns are embedded is prepared. Thereafter, the mother laminate is pressed in the thickness direction, and then the mother laminate is cut into individual laminate ceramic electronic component unit laminates. By firing the laminated body thus obtained, a ceramic sintered body having a plurality of internal electrodes is obtained.
[0003]
The reason why the mother laminate is pressed in the thickness direction is to obtain a dense sintered body and to prevent peeling between ceramic layers, so-called delamination.
Conventionally, the mother laminate is pressed by placing the mother laminate in a mold and pressurizing it with a punch or the like. However, when the mother laminate is pressurized by a pressing method using such a rigid body, the manner in which the press pressure is applied differs between the portion where the internal electrodes of the mother laminate are laminated and the other portion. Therefore, although a large pressing pressure is applied to the portion where the internal electrodes are laminated, the pressing pressure is relatively small in the other portions, and the adhesion between the ceramics is weak except in the portion where the internal electrodes are laminated. Therefore, there is a problem that structural defects such as delamination are likely to occur.
[0004]
Therefore, as shown in FIG. 8, there is proposed a method of pressing with a lower die 104 and an upper punch 105 in a state where elastic bodies 102 and 103 such as rubber sheets are arranged above and below a mother laminated body 101 ( JP-A-7-183157).
[0005]
By applying pressure through the elastic bodies 102 and 103, the difference in the amount of press pressure applied between the portion where the internal electrode patterns 101a overlap and the other portion is reduced. Accordingly, the ceramic layers are firmly adhered to each other at a portion other than the portion where the internal electrodes overlap each other, and structural defects such as delamination can be suppressed.
[0006]
[Problems to be solved by the invention]
However, since pressing is performed using the elastic bodies 102 and 103, the thickness of the portion where the internal electrode patterns overlap is relatively thick and the internal electrodes overlap in the laminated body after the pressure pressing. There was a problem that parts other than the part became considerably thin and a large step was generated. That is, in the laminate obtained by cutting the mother laminate obtained as described above into individual multilayer ceramic electronic component units, the large laminate as shown by the arrow A in FIGS. Steps tend to occur.
[0007]
Therefore, in a multilayer ceramic electronic component using a ceramic sintered body obtained by firing such a multilayer body 111, a large step is generated on the outer surface extending in a direction parallel to the internal electrode surface. When holding and mounting an electronic component, the electronic component may not be sucked and held by a vacuum chuck. Further, when placed on a printed circuit board or the like, the multilayer ceramic electronic component may not be stably positioned at a desired position due to the presence of the step. That is, there is a problem that the reliability in mounting is lowered because of the large steps as described above.
[0008]
The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, the sintered body is sintered uniformly and densely, and not only structural defects such as delamination are difficult to occur, but also reliability in mounting. Another object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component capable of improving the above.
[0009]
[Means for Solving the Problems]
According to a wide aspect of the present invention, a plurality of ceramic sheets, a plurality of internal electrodes disposed so as to overlap each other via the ceramic sheets, and an outer layer ceramic disposed above and below a portion where the plurality of internal electrodes are stacked A method for producing a multilayer ceramic electronic component comprising a first layer, a step of preparing a first mother laminate formed by laminating a first mother ceramic green sheet on which a plurality of internal electrode patterns are formed; A first pressing step of pressing the first mother laminate by disposing elastic sheets that are stretchable at least in the laminating direction above and below the first mother laminate, and after the first pressing step, A second pressing step in which a second mother ceramic green sheet for forming an outer ceramic layer is disposed above and below one mother laminate, and is pressed using a rigid body; A step of cutting the second mother laminate obtained in the second pressing step to obtain a laminate of individual multilayer ceramic electronic component units, and firing the laminate to obtain a sintered body. There is provided a method for producing a multilayer ceramic electronic component comprising a step of obtaining and a step of forming a plurality of external electrodes on the outer surface of the sintered body.
[0010]
In a specific aspect of the present invention, among the press conditions of the first press step, the pressure, temperature, and press time are equal to or less than the press conditions of the second press step.
[0011]
In another specific aspect of the present invention, in the first pressing step, a plurality of first mother laminates are laminated via an elastic sheet therebetween to form a plurality of first mother laminates. Pressed at once.
[0012]
In yet another specific aspect of the present invention, in the second pressing step, the structure in which the ceramic green sheets for forming the outer ceramic layer are disposed above and below the first mother laminate is a rigid body. Thus, a plurality of second mother laminates are obtained at the same time.
[0013]
In another specific aspect of the multilayer ceramic electronic component according to the present invention, in the step of preparing the first mother laminate and the first pressing step, a plurality of the first mother laminate divided in the stacking direction The first mother laminated body portion is prepared, and the plurality of first mother laminated body portions are independently pressed in the first pressing step, and the first mother laminated portion after the first pressing step is prepared. A body part is laminated | stacked in a 2nd press process, the 2nd mother ceramic green sheet for the said outer layer ceramic layer formation is arrange | positioned at the upper and lower sides of this laminated structure, and a 2nd press process is performed.
[0014]
In still another specific aspect of the manufacturing method of the present invention, in the step of preparing the first mother laminate, a plain mother ceramic green sheet having no internal electrode pattern is laminated on top, thereby The internal electrode pattern is covered with a solid mother ceramic green sheet. Therefore, the internal electrode pattern is hardly damaged in the first pressing process.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail by describing specific examples of the present invention.
[0016]
A method of manufacturing a multilayer capacitor as a multilayer ceramic electronic component according to an embodiment of the present invention will be described.
First, a first mother laminate 1 shown in FIG. 1A is prepared. The first mother laminate 1 is formed by laminating a plurality of first mother ceramic green sheets on which a plurality of internal electrode patterns 2 are formed.
[0017]
The step of preparing the first mother laminate 1 is not particularly limited, and is performed according to a normal method for producing a multilayer ceramic electronic component. That is, a plurality of internal electrode patterns 2 are formed by printing a conductive paste on a mother ceramic green sheet or by a thin film forming method such as vapor deposition, plating, or sputtering. A plurality of mother ceramic green sheets on which such a plurality of internal electrode patterns 2 are formed are laminated according to the internal electrode structure of the target multilayer ceramic electronic component. As shown in FIG. 3, in this embodiment, in order to hold the internal electrode pattern 2 on the first mother ceramic green sheet 31 located at the uppermost portion, a plain color having no internal electrode pattern is further provided. A mother ceramic green sheet 32 is laminated. Only one plain mother ceramic green sheet 32 may be used, or a plurality of them may be used. Further, the thickness of the ceramic green sheet of the plain mother may be the same as or different from the ceramic green sheet of the other mother.
[0018]
As shown in FIG. 1A, elastic sheets 3 and 4 such as rubber sheets are arranged above and below the first mother laminate 1, and in this state, pressing is performed using a mold 5 and an upper punch 6. Is done. In pressing, the upper punch 6 is pressed as indicated by the direction of the arrow, that is, by pressing the mother laminate 1 in a direction orthogonal to the internal electrode pattern 2. In addition, 7 shows a frame-shaped member and is used in order to suppress the bulging to the side of the laminated body 1 of the mother. The mother laminate 1 constitutes a portion in which the internal electrode pattern is laminated via the ceramic layer as described above, and a plurality of internal electrodes of the finally obtained multilayer capacitor are overlapped. It does not have a portion corresponding to the outer ceramic layer disposed above and below the portion.
[0019]
The elastic sheets 3 and 4 are made of a material that can expand and contract at least in the laminating direction, and are made of an appropriate elastic material such as rubber, but preferably have a Shore hardness of 90 Hs or less, more preferably 80 Hs or less. It is composed of an elastic material. If the hardness exceeds 90 Hs, the effect using the elastic body may not be sufficiently obtained, and the difference in adhesion between the ceramic green sheets in the portion where the internal electrodes closely overlap each other and the other portions is As a result, structural defects such as delamination may easily occur in a portion other than the portion where the internal electrodes overlap closely.
[0020]
However, the elastic sheet is not limited to one made of an elastic material such as rubber as long as it can expand and contract at least in the laminating direction. For example, a material or member having a hollow or fibrous structure can be used.
[0021]
Next, as shown in FIG. 1B, after the first pressing step, second mother ceramic green sheets 8, 9 for forming outer ceramic layers on the upper and lower sides of the first mother laminate 1 are formed. And the second pressing step is performed using the mold 5, the upper punch 6 and the frame-like member 7. The second mother ceramic green sheets 8 and 9 for forming the outer ceramic layer may be arranged on the upper and lower surfaces of the mother laminate 1.
[0022]
That is, the plurality of second mother ceramic green sheets 8 and 9 may be stacked on the upper surface or the lower surface of the mother laminate 1, respectively. Further, when a plurality of second mother ceramic green sheets are arranged, the plurality of second mother ceramic green sheets may be pressed and adhered to each other in advance. Alternatively, a plurality of second mother ceramic green sheets may be sequentially stacked on the upper or lower surface of the mother laminate 1 prior to the second pressing step.
[0023]
In the second pressing step, the mother laminate 1 is pressed in a direction perpendicular to the internal electrode pattern 2 by moving the upper punch 6 in the direction of the arrow. In this case, the press condition of the second press process is preferably set to be equal to or higher than the press condition of the first press process. In other words, the pressing conditions of the first pressing process are equal to or lower than the pressing conditions of the second pressing process.
[0024]
Here, as described above, the pressing condition includes pressure, temperature, pressing time, and the like, and the pressing condition refers to a level that allows the mother laminate to be pressed. The condition equal to or less than the press condition includes, for example, a condition in which any one of pressure, temperature, and press time is made lower and the other two are made equivalent.
[0025]
In the manufacturing method of the present embodiment, a second mother laminate in which pressurization is completed is obtained through the first and second pressing steps.
In the second pressing step, the pressure may be increased at a stretch to the press pressure to be applied, or may be increased stepwise up to a desired press pressure while repeating pressurization and depressurization.
[0026]
By the way, in the present embodiment, in the first pressing step, the elastic sheets 3 and 4 are arranged and pressed, so the portion where the internal electrode patterns 2 overlap in the mother laminate 1 and the others The pressure is equally applied to the part. Therefore, in the first pressing step, a partial density reduction in the mother laminate 1 is unlikely to occur, and the ceramic green sheets are firmly adhered to each other.
[0027]
In the mother laminate 1 after the first pressing step, the ceramic green sheets constituting the outer ceramic layer are not laminated. However, the first mother laminate 1 after the first pressing step is individually When the multilayer capacitor is cut into multiple multilayer capacitors, the multilayer body 11 shown in FIGS. 2A and 2B is obtained. In this laminated body 11, since the pressing process is performed by a method similar to the prior art shown in FIG. 8 as described above, the ceramic green sheets are firmly adhered to each other, but FIGS. ), A step B is formed between the portion where the internal electrodes are closely overlapped with each other and the other portion. However, the step B is smaller than the step A (see FIG. 9) formed by the conventional method. This is because the difference in thickness between the portion where the internal electrodes are closely overlapped with each other and the other portions are reduced by the amount that the mother ceramic green sheet constituting the outer ceramic layer is not laminated.
[0028]
2A and 2B, an internal electrode 2A formed by cutting the internal electrode pattern 2 described above is embedded in the laminate 11.
Furthermore, in the present embodiment, in the second pressing step described above, pressing is performed under stronger pressing conditions than the first pressing step. Moreover, in the second pressing step, pressing is performed by the mold 5 and the upper punch 6 without using an elastic sheet. That is, since the pressing is performed by the rigid press, in the second mother laminated body 10, the level difference between the portion where the internal electrodes are closely overlapped and the other portion is almost eliminated. Therefore, when the second mother multilayer body is cut into individual multilayer capacitor unit multilayer bodies, as shown in FIGS. 4A and 4B, in the obtained multilayer body 12, internal electrode surfaces and There are almost no steps on the outer surface of the laminate extending in the parallel direction, that is, the upper surface 12a and the lower surface 12b.
[0029]
A ceramic sintered body is obtained by firing the laminate 12. External electrodes 13 and 14 are formed on the outer surface of the ceramic sintered body thus obtained, as shown in FIG. Therefore, the multilayer capacitor 16 using the ceramic sintered body 15 having no step on the upper surface and the lower surface is obtained.
[0030]
In the multilayer capacitor 16, it is difficult to form the above-described steps on the upper surface and the lower surface of the ceramic sintered body 15. Therefore, the multilayer capacitor 16 can be reliably sucked and held by a vacuum chuck, and when placed on a printed circuit board or the like Misalignment is unlikely to occur. Therefore, the mounting reliability can be effectively increased.
[0031]
As described above, in the manufacturing method of the present embodiment, in obtaining the mother laminate, first, only the first mother laminate 1 constituting the portion where the internal electrodes are closely stacked is used as an elastic body. By pressing with a conventional press, the density difference between the portion where the internal electrodes are closely overlapped with each other and the other portions are suppressed, and structural defects such as delamination are suppressed. On the other hand, after the first pressing step, the second mother ceramic green sheets for constituting the outer ceramic layer are arranged above and below the first mother laminated body 1 to perform the second pressing step. In addition, by performing the second pressing step with a rigid press, the step difference between the upper surface and the lower surface of the finally obtained second mother laminate can be suppressed. Therefore, a multilayer capacitor having an outer shape excellent in mounting reliability, such as the multilayer capacitor 16 shown in FIG. 5, can be provided reliably.
[0032]
In the above-described embodiment, the pressure is applied through the elastic sheet with the mold and the upper punch. However, the present invention is not limited to this.
Moreover, in the said Example, as shown in FIG. 1, the 1st mother laminated body 1 was pressurized in the 1st press process, but as shown in FIG. In one pressing step, a plurality of mother laminates 1 may be pressed at a time. In this case, the elastic sheets 21 and 22 are disposed between the upper and lower mother laminates 1.
[0033]
In the process shown in FIG. 6, the plurality of first mother laminates are pressed at a time in the first pressing process. Similarly, in the second pressing process, the plurality of first mothers are also pressed. The mother ceramic green sheets for constituting at least one outer ceramic layer may be laminated on the upper and lower sides of the mother laminate, respectively, and may be pressed at once by a rigid press. In this case, a rigid body between a structure in which at least one second mother ceramic green sheet is laminated above and below the first mother laminated body located above and the same structure located below, For example, a metal plate may be interposed.
[0034]
Moreover, in the said Example, although the 1st press process was performed after obtaining the laminated body 1 of a mother, in the 1st press process, one 1st laminated body of mother was in the thickness direction. After preparing a plurality of divided first mother laminate parts, they may be individually pressed.
[0035]
That is, as shown in FIG. 7A, the first mother laminate portion 1A, which is a part of the first mother laminate 1 shown in FIG. You may implement a 1st press process in the state which has arrange | positioned the bodies 3 and 4 up and down. In that case, the first mother laminate portion 1A and the first mother laminate portion 1B shown in FIG. 7B are independently formed in the first pressing step as described above. Pressed. Then, after pressing the first mother laminate portions 1A and 1B in this way, the first mother laminate portions 1A and 1B are connected to the mold 5 as shown in FIG. The second punching process is performed by overlapping the upper punch 6.
[0036]
In this method, the undulation of the lead portion to the end face of the internal electrode 2A can be reduced.
As described with reference to FIGS. 7 (a) and 7 (b), in the present invention, the step of pressing the first mother laminated body by placing the elastic body vertically is the first mother laminated body. It may be performed after the part of the body divided into a plurality of layers.
[0037]
In the above embodiments, the method for manufacturing a multilayer capacitor has been described. However, the present invention generally relates to a multilayer ceramic electronic component having a structure in which a plurality of internal electrodes are stacked via a ceramic layer, for example, a ceramic multilayer substrate, The present invention can be applied to the production of various multilayer ceramic electronic components such as inductors and multilayer piezoelectric elements.
[0038]
【The invention's effect】
In the method for manufacturing a multilayer ceramic electronic component according to the present invention, the first mother laminate formed by laminating a plurality of first mother ceramic green sheets formed with a plurality of internal electrode patterns is elastic in the vertical direction. Since the sheet is pressed in the first pressing step, the density difference between the portion where the internal electrodes are closely stacked and the other portion can be suppressed, and the occurrence of structural defects such as delamination Can be suppressed. In the second pressing step, at least one second mother ceramic green sheet for forming an outer ceramic layer is disposed above and below the first mother laminate, and pressing is performed using a rigid body. Therefore, a step between the portion where the internal electrodes are densely stacked and the other portion is unlikely to occur on the upper and lower surfaces of the second mother laminate obtained in the second pressing step.
[0039]
Therefore, by firing the individual multilayer ceramic electronic component unit laminate obtained by cutting the second mother laminate, and forming a plurality of external electrodes on the outer surface of the obtained sintered body, A multilayer ceramic electronic component having substantially flat upper and lower surfaces can be obtained with certainty.
[0040]
Therefore, according to the present invention, it is possible to provide a multilayer ceramic electronic component that is less likely to cause peeling and delamination between ceramic layers on the end face, is not only precisely and uniformly fired, but also has excellent mounting reliability. it can.
[0041]
If the pressing condition of the first pressing process is equal to or lower than the pressing condition of the second pressing process, the second pressing process is more strongly pressurized, so that it is obtained after the second pressing process. The upper surface and the lower surface of the second mother laminate thus obtained can be more reliably flattened.
[0042]
In the first pressing step, when the plurality of first mother laminates are laminated via the elastic sheet, the plurality of first mother laminates are pressed at a time, so that the laminated ceramic The manufacturing efficiency of electronic components can be increased.
[0043]
Similarly, in the second pressing step, a structure in which at least one mother ceramic green sheet for forming the outer ceramic layer is disposed above and below the first mother laminate is laminated in a plurality of layers with a rigid body therebetween. In this case, the second mother laminate can be obtained efficiently, and the productivity of the multilayer ceramic electronic component can be increased.
[0044]
In the step of obtaining the first mother laminate and the first pressing step, a plurality of first mother laminate portions are prepared by dividing the first mother laminate in the lamination direction, and the plurality of first mother laminates are prepared. The laminated body portion of one mother is independently pressed in the first pressing step, and the laminated body portion of the first mother that has obtained the first pressing step is laminated in the second pressing step. When the second mother ceramic green sheet for forming the outer ceramic layer is disposed above and below and the second pressing step is performed, in the first pressing step, the first mother laminate is more dense. Therefore, it is possible to reduce the undulation of the internal electrode lead-out portion and further suppress the occurrence of structural defects such as delamination.
[Brief description of the drawings]
FIGS. 1A and 1B are schematic front sectional views for explaining a first pressing step and a second pressing step in a manufacturing method according to an embodiment of the present invention.
FIGS. 2A and 2B are a front cross-sectional view and a side view of a laminated body obtained when the first mother laminated body pressed in the first pressing step is cut into individual laminated capacitor units; Sectional drawing.
FIG. 3 is a schematic cross-sectional view showing a plurality of first mother ceramic green sheets and a plain mother ceramic green sheet that are stacked in the first pressing step.
4 (a) and 4 (b) are front sectional views of the multilayer body obtained by cutting the second multilayer body into individual multilayer capacitor unit multilayer bodies in one embodiment of the present invention. FIG.
FIG. 5 is a front cross-sectional view showing a multilayer capacitor obtained according to an embodiment of the present invention.
FIG. 6 is a front sectional view for explaining a first pressing step of pressing a plurality of first mother laminated bodies at a time in a modification of the present invention.
FIGS. 7A and 7B are a plurality of first mother laminate parts obtained by dividing a first mother laminate into a plurality of thicknesses in another modification of the present invention. After preparing, after performing a 1st press process for every laminated body part of each 1st mother, each schematic front sectional drawing for demonstrating the method of implementing a 2nd press process.
FIG. 8 is a front cross-sectional view for explaining a conventional method of manufacturing a multilayer ceramic electronic component.
9A to 9C are a perspective view, a front sectional view, and a side sectional view of a laminate obtained by a conventional method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st mother laminated body 1A, 1B ... 1st mother laminated body part 2 ... Internal electrode pattern 2A ... Internal electrode 3, 4 ... Elastic sheet 5 ... Mold 6 ... Upper punch 7 ... Frame-shaped member 8 , 9... Second mother ceramic green sheets 11, 12. Laminated body 13. Internal electrodes 14, 15. External electrode 16. Ceramic sintered body 17. Multilayer capacitors 21, 22 ... Elastic sheet 31. Ceramic green sheet 32 ... Solid mother ceramic green sheet

Claims (6)

A multilayer ceramic electronic component comprising: a plurality of ceramic sheets; a plurality of internal electrodes arranged so as to overlap with each other via the ceramic sheet; and an outer ceramic layer arranged above and below a portion where the plurality of internal electrodes are stacked A manufacturing method of
Preparing a first mother laminate formed by laminating a first mother ceramic green sheet on which a plurality of internal electrode patterns are formed;
A first pressing step of pressing the first mother laminate by disposing elastic sheets that can expand and contract at least in the lamination direction above and below the first mother laminate;
After the first pressing step, a second mother step of placing the second mother ceramic green sheet for forming the outer ceramic layer on the top and bottom of the first mother laminate and pressing using a rigid body; Prepared,
Cutting the second mother laminate obtained in the second pressing step to obtain a laminate of individual multilayer ceramic electronic component units;
Firing the laminate to obtain a sintered body;
And a step of forming a plurality of external electrodes on the outer surface of the sintered body. 2. The multilayer ceramic electronic component according to claim 1, wherein among the pressing conditions of the first pressing step, the pressure, temperature, and pressing time are equal to or less than the pressing conditions of the second pressing step. Production method. 2. The plurality of first mother laminates are pressed at a time by laminating a plurality of first mother laminates via an elastic sheet therebetween in the first pressing step. 3. A method for producing a multilayer ceramic electronic component according to 2. In the second pressing step, a structure in which the ceramic green sheets for forming the outer ceramic layer are arranged above and below the first mother laminate is laminated in a plurality of layers with a rigid body therebetween, thereby The manufacturing method of the multilayer ceramic electronic component in any one of Claims 1-3 with which the laminated body of a 2nd mother is obtained simultaneously. In the step of preparing the first mother laminate and the first pressing step, a plurality of first mother laminate portions obtained by dividing the first mother laminate in the stacking direction are prepared, and the plurality The first mother laminated body portion is independently pressed in the first pressing step, and the first mother laminated body portion subjected to the first pressing step is laminated in the second pressing step, and the laminated structure 3. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein a second mother ceramic green sheet for forming the outer ceramic layer is disposed above and below the second pressing step. 6. The multilayer ceramic electronic component according to claim 1, wherein in the step of preparing the first mother laminate, a solid mother ceramic green sheet having no internal electrode pattern is laminated on top. Manufacturing method.

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